High voltage buck inductor doubts

[emontllo]

High voltage buck inductor issues

Hello,

I am designing an offline buck converter with the following specs:
Vin = 500 VDC
Vout = 10 VDC Iout = 120 mA

Isolation is not requiered and I have chosen a buck converter. My questions are:
1. Are standard ferrite core (e.g. Murata 46105C) power inductors adequate for this application?
2. May high voltage cause coil damage or other issues?
3. Do you have any recommendation on inductor technology, size, etc.

Thank you in advance for your response!

Ernest

 

[tsvetelin_velkov]

Hello Ernest,
What is the operating frequency of your new design? Your voltage is really high, why do you want to convert from 500V DC?

The design of buck converter is explained here :

https://www.google.com/url?sa=t&rct...S3kKRQ&usg=AFQjCNHgb0bVZcgn5GnjTeAFo6Wo2JBFvQ

including the inductor calculation, filter capacitor calculation, etc.

Also this one could be interesting for you :

https://www.google.com/url?sa=t&rct...S3kKRQ&usg=AFQjCNGaWhaFe0gkEmVE0CtcRDzwWRbw_g

In case that you really want to convert from 500V DC, I would recommend you to use transformer for galvanic isolation. The voltage that you have is high and dangerous, could destroy the supplied device or injure someone.

The frequency question is very important, because will give you immediately the answer for the inductance and suitable ferrite - together with input/output voltage and current it is in the equation that solves the question what inductance do you need

After you check the attached file and in case you have further questions, pleas write here and I would try to answer you.

Regards,
Tsvetelin

 

[DeepOne]

Possible this will useful:
**broken link removed**

 

[emontllo]

Hello and thank you for your answers!

Isolation is not required for this application and safety will be assured by design. A flyback isolated converter could also work for the application, however, volume and price would be higher...
DeepOne, The topology you sent to me with the VIPER looks nice and thank you for the software. Actually it is quite similar to the one used with POWERINT LinkSwitch-TN, I have to analyze which option is better.
Switching frequency is 120 kHz.

Ernest